Green roofs are not just a trend. They are a commitment that many architects have established with the environment and with the future. But what are they, what are the types and what is the ideal vegetation to use in them?

We have developed a small guide that can help you get into the subject and encourage you to incorporate it into your next projects or homes.

What is a green roof?

In a few simple words, green roofs are a combination of layers of vegetation and membrane that beautify the top/roof of a building.

The system of green roofs can help insulate and provide water and energy management in a building. Also, green roofs help mitigate the greenhouse effect in the environment, as they create habitats that filter pollutants, capture carbon, and even increase the agricultural space in cities.

Types of green Roofs

Tell us what the useful time of a building is, and we’ll tell you what kind of roof suits you. According to experts, there are 3 basic types of green roofs:

• Roofs made of extensive systems. These are the roofs that are installed in areas that are out of reach. For that precise reason, they include low maintenance and self-sufficient vegetation. Extensive systems are thus resistant to drought and frosts.

• Roofs made of semi-intensive systems. This type of roof requires maintenance from time to time. They are an intermediate system between extensive and intensive roofs, so they include a combination of plant types.
• Roofs made of intensive systems. This type of roof requires frequent maintenance. In fact, these systems are considered gardens on a roof, so the possibilities to use plants are almost limitless.

How green?

Although the vegetation to be included in a green roof depends greatly on its typology, and many times on the structure where it will be placed, there is a general rule for these roofs. The soil for a green roof must have a proportion of 70 percent of inorganic material and 30 percent organic material.

A very good idea for the vegetation of green roofs are the mixtures of seeds. For example, for roofs made of extensive systems it’s a good idea to use moss, sedum, and herbs. For roofs made of semi-intensive systems, the best options are grasses, shrubs, small trees, woody plants, and herbs. While, as we already said, the roofs made of intensive systems can house virtually all plants and be treated like a garden.

Some of the most important points to consider when installing a green roof are: the permission (the authority of the zone must give its approval); understand the biodiversity and habitat desired to choose a suitable green roof system; ensure that the green roof substrate contains an adequate volume of organic content to reduce the likelihood of fire; and choosing a built-in maintenance system so it fulfills its objective.

A green roof may be a way to bring nature to a concrete environment, but it also represents a great responsibility. However, modern cities and constructions are increasingly betting on them, since the benefits they bring to the environment and construction are directly proportional to the maintenance requirements. So, the green trend will continue going up to the roof.